Aretha Franklin is "doing really, really good" after undergoing a medical procedure for an undisclosed ailment at a Detroit hospital on Thursday, her cousin Brenda Corbett says.

Concerns about the health of Franklin, the 68-year-old "Queen of Soul", have grown in recent weeks after she canceled all concert dates and personal appearances through May 2011 by order of her doctors.

Franklin said in a statement carried by the Associated Press that her surgery was "highly successful," adding: "God is still in control. I had superb doctors and nurses whom were blessed by all the prayers of the city and the country. God bless you all for your prayers!"

Detroit City Councilwoman JoAnn Watson and others gathered downtown on Wednesday to pray for Franklin following news of her surgery.

Franklin has been overweight for years. According to the U.S. Centers for Disease Control and Prevention, being overweight can lead to several health ailments, such as coronary heart disease, Type 2 diabetes and various forms of cancer.